Divide gesture scroll delta by scale factor
https://bugs.webkit.org/show_bug.cgi?id=106263

Reviewed by Adam Barth.

Gesture scroll deltas were not being adjusted by the frame's scale
factors, resulting in overly fast main-thread scrolling when zoomed
in.

New test: fast/events/touch/gesture/touch-gesture-scroll-div-scaled.html

* page/EventHandler.cpp:
(WebCore::EventHandler::handleGestureScrollCore):


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@139022 268f45cc-cd09-0410-ab3c-d52691b4dbfc